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F. S. WAHL.

INTERNAL COMBUSTlON ENGINE.

APPLICATION FILED NOV-30, 1911.

1,338,056. Patented Apr. 27, 1920.

4 SHEETSSHEET I.

F. S. WAHL.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-30.1917.

1,338,056, Patented Apr. 27, 1920.

4 SHEETS-SHEET 2. 5/

my. Z. i z

F S. WAHL.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-30,1917.

1,338,056, Patented Apr. 27, 1920.

4 SHEETS-SIIEET 3.

F. S. WAHL.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-30,1917.

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FRANK S, WAHL, OF NORTH TONAWANDA, NEW YORK.

INTERNAL-CGMBUSTIGN ENGINE.

Specification of Letters Patent.

Patented A nea 1920.

Application filed November 30, 1917. Serial No. 204,571.

To all whom it may concern Be it known that I, FRANK S. Warm, a citizenof the United States, residing in North Tonawanda, in the county ofNiagara and State of New York, lave invented new and useful Improvementsin Internal-Combustion Engines, of which the following is aspecification.

This invention relates to internal combustion engines and moreparticularly to an engine of this type which works on the twostrolrecycle principle.

Internal combustion engines which are now most generally in use may bedivided into two classes, one known as the twocycle or two-stroke cycleand the other known as the four-cycle or four-stroke.

Other things being equal, a two-cycle engine should develop twice asmuch power as a four-cycle engine inasmuch as the 1m pulses of atwo-cycle engine are tw to that of a four-cycle engine, which, however,has not been the case in actual practice.

Furthermore, most forms of two-cycle engines now on the market utilizethe crank case as a fuel. reservoir which is undesirable, becauseleakage is practically unpreventable and it also renders impossible theuse of the splash-system of oiling. The possibil ty of pro-ignition ofthe compressed gases n the crank case of two-cycle gas engines is another objectionable feature.

l he principal objection to the four-cycle engine is that thesamerequires a reducing gearing for driving cam she ft from the main shaftwhich adds unnecessary weight, complicates the mechanism and increasesthe cost of manufacture and maintenance.

From the foregoing analysis of these two tvpcs of engines, it has beenfound that a two-cycle engine will deliver from one and one-third to oneand one-half of the amount of power developed by a four-cycle engine fora given amount of fuel consumption.

It is the object of this invention to produce engine of the two-cycletype which retains the advantages of he two-cycle and the four-cycletypes of engines and eliminates the objectionable features of both, andto accomplish this in manner which will permit of handling a largervolume of the gaseous mixture than the normal piston displacement, topass this mixture through large ports and passages under sitotable 1ressure so that the supply-0; fuel til-e engine is effected promptly, tolengthen the interval of-time during which the inlet port is open so asto permit the maximimi inflow of the mixture, and to produ;e a thoroughscavenging of the cylinder so as to obtain the maximum power efficiencyfrom the fuel consumed.

My invention has the further object to so organize the means whirhtransmit the power to the crank shaft that the impulse due to theexplosion of the gaseous mixture is applied simultaneously todiametricallyopposite sides of the crank shaft, thereby avoidinghammer-blows on the shaft and the parts associated therewith and alsoavoiding undue wearing of the bearings in which this shaft is journaled.

Another purpose of my invention is to provide means whereby a greatervolume of gaseous mixture is admitted to the cylinder than the ordinarypiston displarement usually affords and to maintain the compression ofthis mixture in the cylinder constant under varying atmosphericconditions by means which are controlled either manually,thermostatically or barometrically, or by a suitable combination of suchcontrolling means. This last-mentioned provision is particularlysuitable for aeroplane engines inasmuch as engines for this service musttravel in and utilize the atmosphere not only at sea level but alsothousands of feet higher where the density of the air is much lowerwhich renders the engine compression variable at different levels andtherefore yields variable power. An engine utilizing a fixed pistondisplacement is incapable of so filling the cylinder as to compensatefor the varying densities of the atmosphere. By hanling greater volumeof the gaseous mixture than the normal piston displacement, contemplatedin the present invention, together with the regulator for adjusting thefuel intake to compensate for variation in atmospheric conditions, it ispossible to maintain the compression of the mixture constant.

In the accompanying drawings: Figure 1 is a vertical section of one formof internal parts when the explosive mixture has reaqhed the limit ofits expansion and is exhausting from the working cylinder. Figs. 3, 4i,and 5 are horizontal sections taken in the correspondin ly numberedlines in Fig. 1.. Fig. 6 is a fragmentary vertical se-tion, on anenlarged scale, of the controlling device which operates to hold themain inlet valve open at the end of the working stroke and the beginningof the compression stroke of the piston. Fig. 7 is a fragmentaryvertical section taken on line 7--7, Fig. 5. Fig. 8 is a verticalsection showing a modification of my invention.

Similar characters of reference refer to like parts throughout theseveral views.

Referring to Figs. 17, 1 represents the hollow base or frame of the gasor internal combustion engine which may be operated by any explosivemedium such as gas, gasolene or kerosene. Within this base is arranged amain or driving shaft 2 which in this instance is arranged horizontallyand. journaled in bearings 3, 3 on the bottom of this base, or in anyother. suitable manner. Between its bearings this shaft is provided witha central crank 4; which projects from one side of the center of thesame and two side cranks 5, 5 which project laterally from the axis ofthe shaft diametrically opposite to the central crank, thislast-mentioned crank being arranged midway between the two side cranks.

6 represents an upright tubular guide whi h is mounted at its lower endon the upper part ofthe engine base or frame and 7 an upright pumpcylinder arranged above the tubular guide and axially in line therewithand having an internal bore than the bore of the tubular guide. Aboutmidway of its height this tubular guide is provided with anexhaustpassage or inanifold 8 which is preferably of annular form and opensinwardly to the bore of this guide and is provided with an outlet 9 onits outer side, as'shown in Fig. 4:, whereby the products of combustionmay be discharged to the atmosphere or conducted to any other suitableplace. For the purpose of cooling the engine, the tubular guide and thepump cylinder are provided with an inclosing shell 10 which forms ajacket 11 therebetween through which water or other cooling medium iscirculated in a manner similar to that commonly practised in engines nowcates lengthwise within the tubular guide and. forms part of the meanswhereby the gaseous fuel or combustible mixture for operating the engineis drawn into the engine and compressed therein and also part of themeans whereby the power to the exploding mixture is transmitted to thecrank shaft. 'At'its lower end this tubular member is ar ranged withinthe base connected on diametrically opposite sides by means of twoconnecting rods 13 with the side cranks of the main shaft, as shown inFigs. 1 and 2. At its upper end this tubular member is connected with aplunger or piston 14 which reciprocates vertically within the pumpcylinder or barrel and forms part of the mixture pumping and compressingmechanism. The lower end of the tubular member 12 is open and its upperend is provided with means for feeding the explosive charge into thesame and also igniting this charge. Between its upper and lower end thismember is provided with an exhaust or outlet for the products ofcombustion from the interior of this member into the exhaust manifold,this exhaust of the tubular member being preferably constructed in theform of an annular row of comparatively narrow slots or openings 15. 16represents the power or firing piston reciprocating lengthwise withinthe tubular member and connected with the tral crank of the main shaftby means pitman or connecting rod 17. The tul'nilar member thus servesas the firing cylinder of the engine; the guide rod of thepump plungeralso serves to deliver halfof the power developed to the crank shaft;and the same also operates in conjunction with the firing piston and theexhaust manifold as the outlet valve mechanism, whereby the exhaust oroutlet of the engine for the spent products of combustion iscontrolled.

The space in the pump cylinder above the pump plunger and the spacewithin the upper part of the tubular member between the pump plunger andthe firing piston, which last-mentioned space forms the engine cylinderproper, are adapted to be placed. in communication or cut off fromcommunication by a valve mechanism which may be variously constructed.The valve mechanism which is shown in Figs. 1 and 9,, is an example ofone which may be used for this purpose and as there shown the samecomprises valve casing or cage 18 which is secured by means of a screwjoint in a vertical opening formed centrally in the pump plunger and thetop of the cylinder, and provided centrally with a port 19 leading fromthe upper part of the pump cylinder to the upper part of the firingcylinder and terminating at its lower end. in a downwardly-facingconical main valve seat 20. 21 represents an outwardly-closing mainintake valve of conical form adapted to engage he valve seat 20 andprovided with an upwardly-projecting valve stem 22 which is guided in anupright guide sleeve 23 which is connected by a bridge 2% forming partof the valve cage 18. The main intake valve is yieldingly held in itsclosed position by means of a spring 25 surrounding the valve stem 22and bearing at its lower end against prolonging the period during whichthis valve is held open and therefore insuring a maximum fuel charge forthe machine. In the form of this controlling device which is shown inFigs. 1, 2 and 6, the same com-- prises an upright cylinder 27 which ismounted on the upper head of the pump cylinder and has the lower end ofits interior communicating with the upper end of the pump cylinder, acontrolling piston 28 moving vertically in this cylinder, an uprightshifting rod 29 secured to the controlling piston and having its lowerend guided in a bridge 30 on the lower part of this cylinder} andarranged vertically in line with the stem of the intake valve while theupper end of this rod is guided in a screw nut or bushing 31 secured tothe top of this cylinder, a spring 32 surrounding the upper part of thisrod and bearing at its lower end against the top of this piston whileits upper end bears against said screw nut and a vent opening 33arranged in the upper part of the controlling cylinder and placing theupper end of the same in communication with the atmosphere. A

On one side of the lower part of the pump cylinder, the same is providedwith a lateral extension 34cwhich contains a supply section 35 of a fuelsupply conduit or passage which communicates with a carbureter or anyother source of supply from which the explosive mixture is drawn and twodelivery sections 36, 37 one of which 36 opens into the upper end of thepump cylinder and the one 3'? opening by a lower branch passage 38 intoth lower end of this cylinder and by an upper branch passage or port 39into this cylinder at a place between its upper and lower Between thesupply conduit section 35 and the delivery conduit section 36 isarranged an inwardly facing valve seat 39 and between the supply conduitsec tion 35 and the delivery conduit section 37 is arranged an inwardlyfacing valve seat 40. 41, 4-2, represent two inwardly-opening puppetvalves which are adapted to engage with the valve-seats 39, 40,respectively, and are guided in their movements by means of uprightvalve stems 43, 4A projecting downwardly, respectively, from theundersides of these valves and guidedin tubular ways 45, 46 on theadjacent lower part of the extension 34, as shown in Figs. 1, 2- and 7.

Any suitable means may be provided for igniting the combustible chargewithin the firing cylinder at the proper time, those shown in Figs. 1and 2 being typical forms of spark plug which is suitable and comprisesa tubular bushing 47 secured in an opening extending vertically throughthe pump piston and the upper head of the firing cylinder andelectrically connected through the metallic parts of the engine with oneside of an electric source so that the side points 48 on the inner endsof this plug form one terminal of the circuit, and a central terminal 49which is electrically connected with the other side of electric source,and an insulating core 50 supporting the central terminal on saidbushing. Inasmuch as this spark plug reciprocates with the firingcylinder and pump plunger an extensible connection is provided betweenthe central terminal and the electric circuit, this being preferablyaccomplished by means of a spring or flexible conductor 51 connected atits lower end with the upper end of the central terminal 49 while itsupper end is connected with a binding post 52 fixedly mounted on theupper end of a. tubular cap 53 which is constructed of insulatingmaterial and mounted on the upper head of the pump cylinder, as shown inr igs. l and 2.

When the parts of the engine are in the position shown in Fig. 1, thefiring or working piston is in its uppermost position, the firingcylinder and plunger are in their lowermost position, the controllingpiston is in its lowermost position, the main intake valve and the checkvalves are closed and the exhaust ports of the firing cylinder arearranged below the firing piston and the exhaust manifold. normaloperation of the engine, a charge of gaseous fuel or mixture iscompressed between the firing piston and the upper part of the firingcylinder and a partially compressed charge of fuel is contained in the 7upper part of, the pump cylinder. Upon now igniting the charge ofexplosive mixture in the firing cylinder the latter together with thepump plunger will be raised and the firing piston will be depressed anda pressure is exerted against the main intake valve which aids inholding the same shut. During this movement of the pump plunger andfiring cylinder and piston the cranks of the main shaft operate ondiametrically opposite sides of the latter and the same is turned with aworking impulse without however sustaining any shock or undue lateralpressure.

Immediately after the pump plunger has effected the initial part of itsupward movement in the pump cylinder this, plunger closes the upperbranch passage 39 and produces a suction through the lower branchpassage 38 into the lower end of the pump At this time, during thecylinder so thatthe check valve 42 is opened and; a portion. ofv thegaseous mixture is drawn from the. carbureter into the lower end of thepump cylinder. After the pump plunger has passed above the upper branchpassage 89 part of the gaseous mixture is drawn through. both the lowerand upper branch passages 38, 39 into the lower end of the cylinderuntil the plunger reaches the upper. endof its stroke, as shown in Fig.2. During the subsequent downward movement of the plunger the checkvalve 42 is closed and the gaseous mixture within the lower part of thecylinder is compressed until the pump plunger passes below and uncoversthe. upper branch passage 39 at which timethe compressed charge ormixture=passes from the lower end of the pump.

cylinder through the lower and upper branch passages 38, 39 into thepump cylinder: abovethe plunger. During the down, ward movement of theplunger the same also draws an additional quantity of gaseousmixturepast; the valve 41 and passage sections 35, 36 into the upper end of thepump cylinder.v The two quantities of gas OIlErdI'iIWIldirectly into theupper part of. the pump cylinder during the downward movement of thelatter and the other drawn indirectly into this end of the cylinderduring the upward and downward stroke of the pump plunger aresubsequently compressed in the upper part of the pump cylinder, during;the next following upward strokeof the pump plunger.

The pressure of the expanding burning mixture in the firing chamber isgreater than the pressure of the gas mixture within the upper end of thepump cylinder, this being partly due to the fact that the latter is oflarger cross sectional area than the firing cylinder. During the lastpart of the firing stroke of the engine during which the firing pistonis in its lower position and the pumpplunger and firing cylinder intheir upper position, the exhaust ports of the firing cylinder registerswith the exhaust manifold and the firing piston uncovers these exhaustports and is arranged below the same. The instant this occursthe prodnets of combustion of the burned mixture escape from. the lower end ofthe firing chamber through the exhaust ports thereof into the exhaustmanifold. This causes the pressure in. the firing cylinder to dropimmediately below that of the compressed gases Within the upper end ofthe pump cylinder whereby the predominating pressure of the fresh gasesin the pump cylinder forces the intake valve to open and causes the liveor fresh charge of gaseous fuel to pass downwardly into the firingcylinder. During this movement the fresh gases spread from thecentralupper part of the firing cylinder over the entire area Within the sameand move downwardly in a compact mass which sweeps the spent gasdownwardly before it and outthrough the ex haust ports so that no deadgas remains in the firing cylinder, thereby increasing the power andefliciency of the engine.

Immediately after the firing piston has, reached its lowermost positionand the firing cylinder its uppermost position the. movement of theseparts is reversed and during the initial part of the subsequent upwardmovement of the firing piston and the downward movement of the firingcylinder the exhaust portsare again closed by the firing piston. so thatthe fresh charge of the. explosive mixture within the firing cylinder iscompressed during the remaining ortion of their compression strokes. When the firing cylinder and firing piston reach the end of theirdownward and upward strokes respectively, the compressed mixture betweenthe same is ignited and the next cycle of operations is repeated asabove described. The exhaust ports are. preferably comparatively narrowbut together provide ample area to avoid any restriction or resistanceto the free escape of the burnt gas and at the same time permitof again closing the exhaust in the shortest possible time.

The pressure of the mixture in the upper part of the pump cylinderduring the upward stroke of the plunger is sufficient to raise thecontrolling piston in opposition with its spring 32 and during the lastpart of the upward movement of the pump plunger and firing cylinder, theupper end of the stem of the main intake valve engages with the lowerend of the shifting rod of the controlling piston, as shown in Fig. 2.As the pressure in the upper end of the pump cylinder decreases byreason. of the intake valve at this time being open and permitting themixture to pass from the pump cylinder into the firin cylinder the 110pressure of the spring 32 prec ominates over the mixture pressureagainst the underside of the controlling piston, thereby causing thispiston to follow the intake valve during the initial part of itsdownward movement 115 with the pump plunger and firing cylinder and holdthis intake valve in its open position until the firing piston hasclosed the exhaust ports of the firing cylinder. After this initialdownward movement of the fir- 12o ing cylinder, the controlling pistonreaches the end of its downward movement in the controlling cylinder andpermits the main intake valve to be closed by the pressure within thefiring chamber and the action of 125 the intake valve spring 25 so thatthe fresh charge or mixture will be compressed with in thefiring-cylinder during the balance of the compression strokes of thiscylinder and 1ts companion piston. By this means a com- 130 plete andthorough scavenging of the firing cylinder is efi'ected and renders thefresh charge perfectly free from inert or spent gas, The formation of anair pocket in the upper end of the controlling cylinder is prevented bythe'vent opening 33 which permits the air to freely enter and leave thisend of this cylinder during the rising and falling movement of itspiston.

When this engine is used for propelling an aeroplane the range of travelwhich varies anywhere from sea level to high altitudes, it is desirableto provide means for varying the admission of gaseous mixture to theengine in accordance with the changes in temperature of the engine andvariations in the condition of atmosphere in which the aeroplane for thetime being is traveling. These means are preferably associated with thecheck valves 41, 42 in the supply conduits and may be controlled eithermanually or thermostatically or barometrically. The means shown inconnection with the check valve 41 in Fig. 7 are manually controlled andcomprise a spring 55 surrounding the lower end of the valve stem 43 andbearing at its upper end against the lower end of the valve stem guide45 while its lower end bears against a screw nut 56 on the threadedlower end of this valve stem. By turning this adjusting screw nut sothat it moves either up or down on its valve stem the tension of thespring 55 which resists the opening movement of this check valve mayberegulated so as to admit a greater or a lesser quantity of gaseousmixture through this particular conduit into the engine by the suctionof the pump plunger. By this means the amount of the mixture may bevaried manually to suit the altitude at which the aeroplane istraveling, the tension on the spring 55 being made lighter so that alarger volume of mixture is admitted when the aeroplane is traveling ata high altitude and the atmosphere is less dense, while. the tension ofthis spring is increased so that the check valve 41 opens less freelyand therefore permits a smaller volume of mixture to enter the enginewhen the aeroplane is traveling at a lower altitude where the atmosphereis more dense.

This same effect may be produced automatically by mechanisms which areresponsive to variations in the density of the atmosphere. Such amechanism is shown in connection with the check valve 42, in Figs. 1, 2and 4, and comprises a shell or casing 57 mounted on the base or otherstationary part of the engine and divided by a movable diaphragm orpartition 58 into a lower closed air chamber 59 and an upper vented airchamber 60 which communicates with the outer atmosphere by means ofopenings .61 in the top of this chamber. I From the central part of thisdiaphragm a shifting rod 62 extends upwardly through a guide 63 in thetop of the upper air chamber, and a spring 64 is employed for connectingthe upper end of the shifting rod 62 with the lower end of the stem 44of the check valve 42. In low altitudes the greater pressure of the airentering the upper chamber 60 through the openings 61 causes thediaphragm to be depressed and the spring 64 to be strained to a greaterextent so as to increase the resistance of the check valve 42 againstopening under the suction action of ,the pump plunger, thereby reducingthe amount of gaseous mixture which is drawn into the engine. Whenhowever, the engine is traveling in high altitudes where the air is lessdense the reduced pressure of the air against the upper sides of thediaphragm causes the tension of the spring 64 to become relaxedaccordingly and thereby permit the check valve 42 to open easier and'allow a proportionately increased volume of gaseous mixture to be drawnby the pump plunger into the engine. The barometric regulator thereforeautomatically adapts the I supply of fuel to the engine in accordancewith the requirement under different atmospheric conditions.

In order to steady the movement of the diaphragm a spring 65 ispreferably mounted on the rod 62 between the top of the casing 57 andthe diaphragm so that it operates to assist in depressing the diaphragm.

In the modified construction of the engine containing my improvementsshown in Fig. 8, the head 66 forming the upper end of the firingcylinder 67 and also part of the pump plunger 68 is provided on itsupper side with heat radiating ribs or fins 69 which carry away some ofthe heat developed in the firing cylinder and warm the incoming gas inthe upper part of the pump cylinder 70 so as to thoroughly vaporize thefuel and promote rapid ignition of the same.

The central terminal 71 of the spark plug in the construction in Fig. 8is provided with upwardly extending brush rod 72 which slides in contactwith a stationary metal disk or plate 7 3 connected with a binding post74. This plate and binding post are mounted on a tubular insulating capsecured to the upper end of the pump cylinder. One side of the electricsource is grounded on the metal parts of the engine so as to connectwith the other terminals 75 of the spark plug and the other side of thesour-re connects with the binding post 74, and during theoperation ofthe engine the brush rod 72 by sliding on the plate 73 keeps theterminals 71, 75 in the electric cirruit for producing the spark forigniting the charge.

The means for controlling the operation "of the=main intake valve 76 inthe construction shown in Fig. 8 comprises a controlling cylinder 77arranged on top of the pump cylinder '70 and opening at its lower endinto the latter while its upper end is provided "with a check'valve 78which permits air to escapefr'om this end of the cylinder but preventsentrance of the same, a controlling piston 79, arranged in thecontrolling cylinder, an'upright connecting rod 80 connected at ltslower end with "the main intake valve 7 6 and "at its upper end with thecontrolling piston 7 9 and a spring 81'surrounding this connectin'g rodand engaging its upper end with a bridge 82 mounted on the pump plunger"68 and its lower end against a shoulder 84cm the connecting rod 80 soas to yieldingly hold the intake valve in its *open osition. During thedownward stroke or the firing cylinder the intake'valve 76 is "hlds'hut"by "the gaseous mixture therein which" is being compressed and also bythe upward pulling'efie'ct of thecontrolling pis- "ton =79 as the latterin its descent in the controlling cylinder produces a partial vacuum inthe upper end of this cylinder, these combined forces being reater thanthe tension of the spring 81. he ascent'of the controlling piston iscomparatively free inasmuch as the check valve *7 6 at this time opensand permits the escape of the air from theup'per endof the controllingcylinder, Whichenable's the expanding burning gases in thefiringcylinder to hold'the main ini take valve 7 6- shut during theupward stroke of the firing cylinder. When however the exhaust ports ofthe firing cylinder are opened by'the 'firing piston during the lastpart of the firingor expansion strokes of these members and the pressurewithin the fii-ing 'cylinderdrops, due to the escape of thespent gases,then the pressure of the spring '81 together with the'pressure ofthecompressed charge of gasin the upper end of the pump cylinder opens themain'valve 76 T and i this gas 1 rushes into the firing oylinderandfills-the same asthe 'burnt gas esca "es therefrom. v

p n Fig. 8 are also shown means for regulating the-explosive mixturesupply to the engine'whih-are responsiveto variations in *the thermalconditions in the engine as Well 'as 'fluetuiations in'the density ofthe atmosphere. As is well known a hot mixture cannot be-compre'ssed tothe samedegree as a cold-one: of the same volume. To thoroughly vaporizethe fuel, especially the lower grades, requires considerable-heat. Inorder to obtain the highest'-efiiciency,- anengine s'hould becapable o'fusing' 'a hot mixture in Which the fuel has been thoroughly vapori edand at the same time maintain its degree of compression constant. Theexample of means'in Fig. 8 showingsu'ch a thermostatic control combinedwith a bitIOIIlQtIlG control is constructed as follows 85 represents abarometric shell or casing mounted on a stationary part of the engineand divided by a flexible diaphragm or partition 86 into a lower sealedair chamber 87 and an upper vented air chamber 88 which is open to theatmosphere. 89 represents a shifting rod guided in the upper part of theshell and'90 a spring surrounding this rod and interposed between thetop of the shell and" the diaphragm'so as toyieldingly hold the latterin a depressed position. 91 represents a regulating lever pivoted at oneend to the upper endof the-diaphragm rod. To the central part of thisleveris connected a spring 92 which is in turn connected with thelowerend of the valve rod 93 of the check valve 94 arranged inthe "fuelsupply conduit 95 of the engine.

96 represents a pipe orconduitforming part of the system whereby wateris circulated around various part's ofthe engine which are'heated 'forthe purpose of'cooling the same. In this water conduit is arranged athermostatic -rod=or ele'ment97 which is adapted to-expand and contractin response to a rise and {fall in the temperature of the water passingthrough the circulating conduit. 'One end of this thermostatic rod isxed on thefpipe, as shown at 9'8, and=the other is connected with a rockarm99 arranged withinthe pipe 96 and mounte'd'on a rock shaft 100journaled in suitable bearings on this pipe. "Outsideo'f the lattertherock shaft l00is provided with a rock arm 101 WhlCh'lS connected by arod 102 with the other end of the lever'9l.

As "the temperature of the engine increases, the temperature of theexplosive mixture is-also raised. s a result the thermostatio element 97in t 1e Water conduit exp ands and shifts the "regulating lever 91 so asto reduce the tension on the spring" 92 and permit the check valve 94to'open easier. A greater volume of mixture is thereby allowed toenterthe' engine and be compressed, whereby the com ression-ismaintained constant. Any changes in the density of the air will causethediaph'ragm 86to rise or fall and thereby' also-lessen o1"inc're'asethe tension-of the spring'92 and "either increase or decrease the volumeof mixture which is permitted" to enter the engine.

I claim as-my invention 1. An internal combustion engine comprising areciprocating firing cylinder, a'recipro'cating firing piston arrangedin said cylinder and moving oppositely thereto, and means for Isupplying --said "cylinder with an explosive medium comprising a pumplunger connected with said 1 firing cylinder and a ump c linder inWhichsaid' phlhger-Teciprocates and is adapted to receive an explosivemedium on opposite sides of said plunger.

2. An internal combustion engine comprising a reciprocating firingcylinder, a reciprocating firing piston arranged in said cylinder andmoving oppositely thereto, and means for supplying said cylinder with anexplosive medium comprising a pump plunger connected with said firingcylinder, and a pump cylinder in which said plunger reciprocates and isadapted to receive an explosive medium on opposite sides of saidplunger, the diameter of said plunger and the bore of said pump cylinderbeing greater than the diameter of the periphery of said firingcylinder.

3. An internal combustion engine comprising a reciprocating firingcylinder, a re ciprocating firing piston arranged in said cylinder andmoving oppositely thereto. and means for supplying said cylinder with anexplosive medium comprising a pump plunger connected with said firingcylinder and a pump cylinder in which said plunger reciprocates and isadapted to receive an explosive medium on opposite sides of saidplunger, said pump cylinder being provided with a supply passage whichcommunicates with said cylinder at its lower end and at a place betweenits upper and lower ends.

4:. An internal combustion engine com prising a reciprocating firingcylinder, a reciprocating firing piston arranged in said cylinder andmoving oppositely thereto. and means for supplying said cylinder with anexplosive medium comprising a pump plunger connected with said firingcylinder, a pump cylinder in which said plunger reciprocates and isadapted to receive an explosive medium on opposite sides of saidplunger, said pump cylinder being provided with a supply conduit havingan outer section, an inner section which communicates with said pumpcylinder at its lower end and at a place between its upper and lowerends, and a valve seat between said inner and outer sections and aninwardly opening check valve engaging said seat.

5. An internal combustion engine comprising a reciprocating firingcylinder, a reciprocating firing piston arranged in said cylinder andmoving oppositely thereto. and means for supplying said cylinder with anexplosive medium comprising a pump plunger connected with said firingcylinder, a pump cylinder in which said plunger reciprocates and isadapted to receive an explosive medium on opposite sides of saidplunger. said pump cylinder being provided with a supply conduit havinga section which opens into the lower end of said pump cylinder' and at aplace between its upper and 6. An internal combustion engine comprisinga reciprocating firing cylinder, a reciprocating firing piston arrangedin said cylinder, a pump plunger connected with said cylinder, a pumpcylinder which receives said plunger, an intake valve arranged in saidplunger, and means for controlling the opening and closing of saidintake valve comprising a controlling cylinder opening at its inner endinto said pump cylinder and a piston arranged in said controllingcylinder and operatively related to said intake valve.

7. An internal combustion engine comprising a reciprocating firingcylinder, a reciprocating firing piston arranged in said cylinder. apump plunger connected with said cylinder, a pump cylinder whichreceives said plunger, an intake valve arranged in said plunger, andmeans for controlling the opening and clos ng of said intake valvecomprising controlling cylinder opening at its inner end into said pumpcylinder. a controlling piston arranged in said controlling cylinder, arod connecting said intake valve and controlling p ston. and a springoperating normally to hold said intake valve open.

8. An internal combustion engine comprising a reciprocating firingcylinder, a reciprocating firing piston arranged in said cylinder. apump plunger connected with said cylinder. a pump cylinder whichreceives said plunger, an intake valve arranged in said plunger, meansfor controlling the open ng and clos ng of s d intake valve compr singcontrolling cylinder opening at its inn r end into said pum cylin der. acontrolling piston arranged in said controlling cylinder. a rod connectng said intake valve and controll ng p ston. a spr ng operatin normallyto hold s d intake valve open. and an outwardly opening check valvearranged on the outer end of said controlling cylinder.

9. An internal combustion engine compris ng a pump cylinder. a pumpplunger arranged in said pump cylinder. a reciprocating firing cylin erconnec ed with said pump plunger and having a head one side of which isexposed to the interior of said pump c linder and provided with heat rada ing fins which operate to ra se the temperature of the fuel in saidpump cylinder, and a working piston arranged in said firing cylinder.

FRANK S. WAHL.

